Netflix accounted for 31.6% of the Internet traffic in North America, according to Sandvine's latest Global Internet Phenomena Report for the second half of 2013, which used data from September.

That means Netflix is still the leader, though its share fell from last year's 33%. In second place, YouTube looks like it's closing the gap somewhat by bringing in 18.7% of usage. Last September, YouTube made up 14.8%.

In fact, those two sites together accounted for more than half of Web usage. A year ago, Netflix and YouTube accounted for 47.8% of what people were consuming, and though Netflix has dipped slightly, YouTube's share growth pushed the two outlets to a combined 50.3%.

Interestingly, the portion taken up by BitTorrent, the best-known Internet technology used for file-sharing, has fallen year-over-year from 5.9% to 4% as people turn to more legal means of consuming content, and it's nowhere near where it was a few years ago. Still, it was ahead of iTunes, which generated 3.27%.

Amazon.com, which runs its Prime Instant service as a competitor to Netflix, was also in the top 10, but its share fell year-over-year from 1.75% to 1.31%, even as it has added content.

"Given the content investments Amazon has made in their prime instant video offering and management’s comments about increased users and usage, we would have expected Amazon’s share to be on the rise, especially given how small the base is relative to Netflix," said BTIG Research analyst Richard Greenfield in a blog post.

Hulu came in at No. 10, behind Facebook, a bit lower than last year and down significantly from the spring, but Greenfield attributed that dip to a lack of fresh shows from broadcasters.